I dont understand why the r9 270x on mantle is getting less of a performance increase than the r7 260x card. I mean the r9 280x can pull around 28% more performance but the card under it can pull less than a card way below it. It doesnt make sense. Is mantle unoptimized for the r9 270x? http://cdn2.wccftech.com/wp-content/uploads/2014/02/Mantle-A10-7700K.jpg

Mantle performance for the AMD Radeontm HD 7000/HD 8000 Series GPUs and AMD Radeontm R9 280X and R9 270X GPUs will be optimized for BattleField 4tm in future AMD Catalysttm releases. These products will see limited gains in BattleField 4tm and AMD is currently investigating optimizations for them.